Minnesota’s power plants have not had a great year. One of the two 550 MW units at Xcel Energy’s Prairie Island plant shut down for a week in early August when its two emergency diesel generators suffered exhaust leaks. The 600 MW nuclear plant in Monticello was shutdown for three weeks starting November 19, 2011 due to low oil pressure in its turbines, closed again early this August for one week to repair a leaking pipe in the plant’s concrete cement structure, and shut down unexpectedly in September of this year when workers were testing a transformer switch.
But perhaps less known is that Minnesota’s largest electricity generation source, the 900 MW coal-fired unit at Xcel’s Sherburne County Generation Station (Sherco), has been offline since November of 2011. An explosion at the plant caused significant damage, and the unit is expected to be offline until March 2013. Thankfully, no one was hurt in the accident.
- Prairie Island — one (of 2 units) shutdown, for a week in August
- Monticello — three–week shutdown, Nov 2011
— one-week shutdown, Aug 2012
— two-day shutdown, Sep 2012
- Sherco — offline Nov 2011 – March 2013
So essentially, according to the U.S. Energy Information Administration, Minnesota has had 5.4% (Sherco 3) of its total 2010 electricity generation capacity offline for almost a year, with an additional 6.9% (the two nuclear units) coming off and on intermittently and at times unexpectedly.
And nothing has happened. The lights didn’t go off and rates didn’t go up. In fact, after the Sherco 3 unit went down there was concern as to where the substitute electricity would come from. But Xcel increased generation at the High Bridge (St. Paul) and Riverside (Minneapolis) natural gas plants and purchased electricity from elsewhere on the grid.
Utilities that use electricity from the Sherco 3 unit said they have not had to raise rates due to the plant outage because replacement power has been reasonably priced. This is likely thanks to continuing low natural gas prices, cheap wind resources and an increasingly flexible grid that expands access to the cheapest available generation sources elsewhere in the region.
To me this begs the question: do we need the Sherco 3 unit moving forward? Xcel claims that the way they have compensated for the downed unit is not sustainable. But as I’ve argued before, we longer need large coal and nuclear power plants to provide continual electricity that way we did in the 20th century.
As Xcel completes and reports this year’s Integrated Resource Plan to the Minnesota Public Utilities Commission later this month, it should be asked to consider a future without the Sherco 3 unit and its other coal-fired sources. The last year has shown that our state’s grid can operate without it with minimal impact on the system and at minimal cost to ratepayers.